Heretofore, several reports have been made about 2,4-diphenyl-2-oxazoline compounds. See, for example, Tetrahedron Letters, 22 (45), 4471-4474 (1981); Chemical Abstracts, 98, 160087k (1983); and J. Chem., 52, 2523-2530 (1987), etc.
Japanese Patent Official Announcement No. 501962/1982 (=PCT International Publication No. WO 82/02046) discloses .DELTA..sup.2 -N-heterocyclic compounds, for example 2,4-diphenyl-2-oxa- or -thia-zoline derivatives and 2-Phenyl-4-benzyl-2-oxa- or -thia-zoline derivatives, useful as intermediates for preparation of effective ingredients of pharmaceuticals and/or as compounds having, as they are, biological actions, e.g. as an antidiabetic drug.
However, the above-mentioned literatures do not mention at all activities of the compounds disclosed therein on pests noxious to agrohorticultural crops, for example insects, mites, etc.
On the other hand, the present inventors found that a series of 2,4-diphenyl-2-oxa- or -thia-zoline derivatives represented by the following general formula (A) ##STR2## wherein, X.sup.1 and X.sup.2 are the same or different, and each denote a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a trifluoromethyl group or a trifluoromethoxy group;
Y.sup.1 and Y.sup.2 are the same or different, and each denote a hydrogen atom, a lower alkyl group, a lower alkoxy group, a lower alkylthio group, a cyano group, a nitro group, a halogen atom or a trifluoromethyl group; PA1 Z denotes an oxygen or sulfur atom; and n is 0 or 1; PA1 (1) Y.sup.1 and Y.sup.2 are not simultaneously hydrogen atoms, PA1 (2) when n is 0 and both X.sup.1 are hydrogen atoms, or when n is 1, and X.sup.1 and X.sup.2 are the same or different and each are a hydrogen atom, a fluorine atom, a chlorine atom or a bromine atom, Y.sup.1 and Y.sup.2 are the same or different, and each denote a lower alkyl group, a lower alkoxy group, a lower alkylthio group, a cyano group, an iodine atom or a trifluoromethyl group, and PA1 (3) X.sup.1 or X.sup.2 and Y.sup.1 or Y.sup.2 cannot denote alkyl groups having 4 to 6 carbon atoms at the 2- or 6-position of the benzene ring, have excellent insecticidal and miticidal activities against harmful insects which are parasitic on useful plants, and proposed them (see Japanese Laid-Open patent Publication No. 85268/1990=U.S. Pat. No. 4,977,171 and EP 345775A1).
provided that